I really don't know your exact lawn/home/street set up but at 2:15am a call to the police to report strangers having an arguement in my front yard I would deem as appropriate. I think that the chances were good that they may have been up to something no good and the police checking their ID's may be good information for them to have. Besides, sometimes that graveyard shift can get pretty boring and the officers may have welcomed a chance to check it out.